Larger diameter cables and cables with multiple shields have less leakage.Ĭommon applications of coaxial cable include video and CATV distribution, RF and microwave transmission, and computer and instrumentation data connections. This property makes coaxial cable a good choice both for carrying weak signals that cannot tolerate interference from the environment, and for stronger electrical signals that must not be allowed to radiate or couple into adjacent structures or circuits. Further, electric and magnetic fields outside the cable are largely kept from interfering with signals inside the cable, if unequal currents are filtered out at the receiving end of the line. When using differential signaling, coaxial cable provides an advantage of equal push-pull currents on the inner conductor and inside of the outer conductor that restrict the signal's electric and magnetic fields to the dielectric, with little leakage outside the shield. Normally, the outside of the shield is kept at ground potential and a signal carrying voltage is applied to the center conductor. The cable is protected by an outer insulating jacket. Coaxial cable also provides protection of the signal from external electromagnetic interference.Ĭoaxial cable conducts electrical signal using an inner conductor (usually a solid copper, stranded copper or copper plated steel wire) surrounded by an insulating layer and all enclosed by a shield, typically one to four layers of woven metallic braid and metallic tape. This allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other types of transmission lines. One advantage of coaxial over other types of radio transmission line is that in an ideal coaxial cable the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. Its applications include feedlines connecting radio transmitters and receivers to their antennas, computer network (e.g., Ethernet) connections, digital audio ( S/PDIF), and distribution of cable television signals. Applications Ĭoaxial cable is used as a transmission line for radio frequency signals. In his 1880 British patent, Oliver Heaviside showed how coaxial cable could eliminate signal interference between parallel cables.Ĭoaxial cable was used in the first (1858) and following transatlantic cable installations, but its theory was not described until 1880 by English physicist, engineer, and mathematician Oliver Heaviside, who patented the design in that year (British patent No. It differs from other shielded cables because the dimensions of the cable and connectors are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a transmission line. It is used in such applications as telephone trunk lines, broadband internet networking cables, high-speed computer data busses, cable television signals, and connecting radio transmitters and receivers to their antennas. The term coaxial refers to the inner conductor and the outer shield sharing a geometric axis.Ĭoaxial cable is a type of transmission line, used to carry high-frequency electrical signals with low losses. æ k s/) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material) many coaxial cables also have a protective outer sheath or jacket. Coaxial cable, or coax (pronounced / ˈ k oʊ.

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